The objective of this article is to provide the basic information on the technical design specifications and criteria, technical terms and equipment parameters appeared in the wind farm grid connection code. For example, power quality issues, their cause and impact on the system performances, as referred to in the codes, will be discussed and explained. The technical specifications include permitted voltage and frequency variations in addition to power quality measures such as limits of harmonic distortion, phase unbalance, and flickers. Wind turbine generating unit operational limits, capability requirements, active power and frequency control, reactive power and voltage control, power factor, etc. will be explained and discussed. The article provides an updated summary of invited tutorials on codes presented at national and international conferences [1]-[3].